1. Field of the Invention
The present invention relates to a lithographic apparatus with a planar motor driven support.
2. Description of the Related Art
A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such a case, a patterning device, which is alternatively referred to as a mask or a reticle, may be used to generate a circuit pattern to be formed on an individual layer of the IC. This pattern can be transferred onto a target portion (e.g. including part of, one, or several dies) on a substrate (e.g. a silicon wafer). Transfer of the pattern is typically via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate. In general, a single substrate will contain a network of adjacent target portions that are successively patterned. Conventional lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing an entire pattern onto the target portion at once, and so-called scanners, in which each target portion is irradiated by scanning the pattern through a radiation beam in a given direction (the “scanning”-direction) while synchronously scanning the substrate parallel or anti-parallel to this direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.
The patterning device is supported by, or held to, a patterning support being movable with six degrees of freedom (DOF) by a patterning drive arrangement. The substrate is supported by, or held to, a substrate support being movable with six DOF by a substrate drive arrangement. The driven patterning support and the driven substrate support are conventionally referred to as stages, where the patterning support may also be referred to as reticle stage, and the substrate support may also be referred to as wafer stage. The lithographic apparatus may include still other supports containing a drive arrangement, and these supports may likewise be referred to as stages.
It is desirable to very accurately position the stages in a lithographic apparatus to be able to obtain substrates having the required patterned structures, which may be very fine, during operation of the lithographic apparatus.
Conventionally, a drive arrangement of a stage from a long-stroke module and a short-stroke module is composed. The drive arrangement for the short-stroke module provides a positioning of the stage support relative to the long-stroke module. The drive arrangement for the long-stroke module provides a positioning of the long-stroke module relative to a frame or base. Therefore, in a positioning of a stage including a long-stroke module and a short-stroke module, the drive arrangement for the long-stroke module generates forces to move both the long-stroke module and the short-stroke module, whereas the drive arrangement for the short-stroke module generates forces to move only the short-stroke module (relative to the long-stroke module). Thus, forces needed to move the short-stroke module are generated twice, both by the long-stroke module and by the short-stroke module, which leads to a high energy consumption of the long-stroke module drive arrangement, and may cause heating problems, as well as limitations to accuracy and performance of the lithographic apparatus.
U.S. Pat. No. 6,891,599 discloses an embodiment of a stage apparatus including a main stage (such as a reticle stage) and a sub-stage, where cables and tubes, such as current supply cables, communication/sensor cables and cooling fluid tubes, leading from a frame or base to the main stage, are partly mounted between the base and the sub-stage, and partly mounted between the sub-stage and the main stage. A motor is provided between the sub-stage and the main stage for a short stroke positioning, and controlled such that the distance between the sub-stage and the main stage will change only in the range of several tens of micrometers. Disturbances caused by the cables and tubes between the base and the sub-stage during movement of the stage apparatus thus need not cause disturbances affecting the main stage. The main stage and the sub-stage are driven by linear motors with a long stroke in an Y direction, and a short stroke in an X direction.